Externally-applied patient interface system and method

ABSTRACT

A tissue closure treatment system and method are provided with an external patient interface. A first fluid transfer component (FTC 1 ) can be placed directly on a suture line for transferring fluid exuded therethrough. An underdrape is placed over FTC 1  and includes a slot exposing a portion of same. A second fluid transfer component (FTC 2 ) is placed over the underdrape slot in communication with FTC 1 . Negative pressure is applied to FTC 2  through a connecting fluid transfer component (FTC 3 ). The tissue closure method includes a manual operating mode using a manual suction device with an automatic shut off for discontinuing suction when a predetermined volume of fluid has been drained. An automatic operating mode utilizes a microprocessor, which can be preprogrammed to respond to various patient and operating conditions. The method proceeds through several phases with different components in place and different patient interface functions occurring in each.

CROSS-REFERENCE TO RELATED APPLICATIONS

Continuation-in-part of U.S. patent application Ser. No. 10/409,225,filed Apr. 8, 2003, U.S. Pat. No. 6,936,037, which is acontinuation-in-part of U.S. patent application Ser. No. 10/334,766,filed Dec. 31, 2002, U.S. Pat. No. 6,951,553.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical devices and methodsfor treating closed wounds and incisions and for managing moisturetherein, and in particular to a system and method for draining and/orirrigating tissue separations, such as surgical incisions, and forcompressing and stabilizing a dissected or traumatized field withambient air pressure created by an external patient interface componentand a vacuum source.

2. Description of the Related Art

Tissue separations can result from surgical procedures and other causes,such as traumatic and chronic wounds. Various medical procedures areemployed to close tissue separations. An important consideration relatesto securing separate tissue portions together in order to promoteclosure and healing. Incisions and wounds can be closed with sutures,staples and other medical closure devices. The “first intention”(primary intention healing) in surgery is to “close” the incision. Forload-bearing tissues, such as bone, fascia, and muscle, this requiressubstantial material, be it suture material, staples, or plates andscrews. For the wound to be “closed,” the epithelial layer must seal. Toaccomplish this, the “load bearing” areas of the cutaneous andsubcutaneous layers (i.e., the deep dermal elastic layer and thesuperficial fascia or fibrous layers of the adipose tissue,respectively) must also at least be held in approximation long enoughfor collagen deposition to take place to unite the separated parts.

Other important considerations include controlling bleeding, reducingscarring, eliminating the potential of hematoma, seroma, and“dead-space” formation and managing pain. Dead space problems are moreapt to occur in the subcutaneous closure. Relatively shallow incisionscan normally be closed with surface-applied closure techniques, such assutures, staples, glues and adhesive tape strips. However, deeperincisions may well require not only skin surface closure, but alsotime-consuming placement of multiple layers of sutures in theload-bearing planes.

Infection prevention is another important consideration. Localizedtreatments include various antibiotics and dressings, which control orprevent bacteria at the incision or wound site. Infections can also betreated and controlled systemically with suitable antibiotics and otherpharmacologics.

Other tissue-separation treatment objectives include minimizing thetraumatic and scarring effects of surgery and minimizing edema.Accordingly, various closure techniques, postoperative procedures andpharmacologics are used to reduce postoperative swelling, bleeding,seroma, infection and other undesirable, postoperative side effects.Because separated tissue considerations are so prevalent in the medicalfield, including most surgeries, effective, expedient, infection-freeand aesthetic tissue closure is highly desirable from the standpoint ofboth patients and health-care practitioners. The system, interface andmethod of the present invention can thus be widely practiced andpotentially provide widespread benefits to many patients.

Fluid control considerations are typically involved in treating tissueseparations. For example, subcutaneous bleeding occurs at the fascia andmuscle layers in surgical incisions. Accordingly, deep drain tubes arecommonly installed for the purpose of draining such incisions.Autotransfusion has experienced increasing popularity in recent years asequipment and techniques for reinfusing patients' whole blood haveadvanced considerably. Such procedures have the advantage of reducingdependence on blood donations and their inherent risks. Serous fluidsare also typically exuded from incision and wound sites and requiredrainage and disposal. Fresh incisions and wounds typically exude bloodand other fluids at the patient's skin surface for several days duringinitial healing, particularly along the stitch and staple lines alongwhich the separated tissue portions are closed.

Another area of fluid control relates to irrigation. Various irrigantsare supplied to separated tissue areas for countering infection,anesthetizing, introducing growth factors and otherwise promotinghealing. An effective fluid control system preferably accommodates bothdraining and irrigating functions sequentially or simultaneously.

Common orthopedic surgical procedures include total joint replacements(TJRs) of the hip, knee, elbow, shoulder, foot and other joints. Theresulting tissue separations are often subjected to flexure and movementassociated with the articulation of the replacement joints. Although thejoints can be immobilized as a treatment option, atrophy and stiffnesstend to set in and prolong the rehabilitation period. A better option isto restore joint functions as soon as possible. Thus, an importantobjective of orthopedic surgery relates to promptly restoring topatients the maximum use of their limbs with maximum ranges of movement.

Similar considerations arise in connection with various other medicalprocedures. For example, arthrotomy, reconstructive and cosmeticprocedures, including flaps and scar revisions, also require tissueclosures and are often subjected to movement and stretching. Otherexamples include incisions and wounds in areas of thick or unstablesubcutaneous tissue, where splinting of skin and subcutaneous tissuemight reduce dehiscence of deep sutures. The demands of mobilizing theextremity and the entire patient conflict with the restrictions ofcurrently available methods of external compression and tissuestabilization. For example, various types of bandage wraps andcompressive hosiery are commonly used for these purposes, but noneprovides the advantages and benefits of the present invention

The aforementioned procedures, as well as a number of other applicationsdiscussed below, can benefit from a tissue-closure treatment system andmethod with a surface-applied patient interface for fluid control andexternal compression.

Postoperative fluid drainage can be accomplished with variouscombinations of tubes, sponges, and porous materials adapted forgathering and draining bodily fluids. The prior art includestechnologies and methodologies for assisting drainage. For example, theZamierowski U.S. Pat. Nos. 4,969,880; 5,100,396; 5,261,893; 5,527,293;and 6,071,267 disclose the use of pressure gradients, i.e., vacuum andpositive pressure, to assist with fluid drainage from wounds, includingsurgical incision sites. Such pressure gradients can be established byapplying porous sponge material either internally or externally to awound, covering same with a permeable, semi-permeable, or imperviousmembrane, and connecting a suction vacuum source thereto. Fluid drawnfrom the patient is collected for disposal. Such fluid controlmethodologies have been shown to achieve significant improvements inpatient healing. Another aspect of fluid management, postoperative andotherwise, relates to the application of fluids to wound sites forpurposes of irrigation, infection control, pain control, growth factorapplication, etc. Wound drainage devices are also used to achievefixation and immobility of the tissues, thus aiding healing and closure.This can be accomplished by both internal closed wound drainage andexternal, open-wound vacuum devices applied to the wound surface.Fixation of tissues in apposition can also be achieved by bolus tie-overdressings (Stent dressings), taping, strapping and (contact) casting.

Surgical wounds and incisions can benefit from tissue stabilization andfixation, which can facilitate cell migration and cell and collagenbonding. Such benefits from tissue stabilization and fixation can occurin connection with many procedures, including fixation of bone fracturesand suturing for purposes of side-to-side skin layer fixation.

Moisture management is another critical aspect of surgical wound careinvolving blood and exudate in deep tissues and transudate at or nearthe skin surface. For example, a moist phase should first be provided atthe epithelial layer for facilitating cell migration. A tissue-dryingphase should next occur in order to facilitate developing the functionalkeratin layer. Moisture management can also effectively controlbacteria, which can be extracted along with the discharged fluids.Residual bacteria can be significantly reduced by wound dryingprocedures. In some cases such two-stage moist-dry sequential treatmentscan provide satisfactory bacterial control and eliminate or reducedependence on antibiotic and antiseptic agents.

Concurrently with such phases, an effective treatment protocol wouldmaintain stabilization and fixation while preventing disruptive forceswithin the wound. The treatment protocol should also handle varyingamounts of wound exudate, including the maximum quantities thattypically exude during the first 48 hours after surgery. Closed drainageprocedures commonly involve tubular drains placed within surgicalincisions. Open drainage procedures can employ gauze dressings and otherabsorptive products for absorbing fluids. However, many previousfluid-handling procedures and products tended to require additionalclean-up steps, expose patients and healthcare professionals to fluidcontaminants and require regular dressing changes. Moreover,insufficient drainage could result in residual blood, exudate andtransudate becoming isolated in the tissue planes in proximity tosurgical incisions.

Still further, certain hemorrhages and other subdermal conditions can betreated with hemostats applying compression at the skin surface. Freefluid edema resorption can be expedited thereby.

Heretofore there has not been available an externally-applied patientinterface system and the method with the advantages and features of thepresent invention.

SUMMARY OF THE INVENTION

In the practice of the present invention, a system and method areprovided for enhancing closure of separated tissue portions using asurface-applied patient interface. Subsurface drainage, irrigation andautotransfusion components can optionally be used in conjunction withthe surface-applied, external interface. The external interface can beadvantageously placed over a stitch or staple line and includes aprimary transfer component comprising a strip of porous material, suchas rayon, applied directly to the patient for wicking or transferringfluid to a secondary transfer component comprising a sponge or foammaterial. An underdrape is placed between the transfer elements forpassing fluid therebetween through an underdrape opening, such as aslot. An overdrape is placed over the secondary transfer component andthe surrounding skin surface. The patient interface is connected to anegative pressure source, such as a vacuum assisted closure device, wallsuction or a mechanical suction pump. A manual control embodimentutilizes a finite capacity fluid reservoir with a shut-off valve fordiscontinuing drainage when a predetermined amount of fluid iscollected. An automatic control embodiment utilizes a microprocessor,which is adapted for programming to respond to various inputs incontrolling the operation of the negative pressure source. A closedwound or incision treatment method of the present invention involvesthree phases of fluid control activity, which correspond to differentstages of the healing process. In a first phase active drainage ishandled. In a second phase components can be independently orsequentially disengaged. In a third phase the secondary transfercomponent can optionally be left in place for protection and to aid inevacuating any residual fluid from the suture/staple line through theprimary transfer component.

In other embodiments of the invention, components of the dressing systemcan be premanufactured for efficient application. A foam piece can beprovided with a full or partial rayon cover and a close-fittingoverdrape. An access panel with a reclosable seal strip can be installedon the overdrape for access to the foam pieces and the wound area. Apremanufactured external dressing can be provided with a sheathreceiving a foam piece, which is accessible through a reclosable sealstrip for replacement or reorientation. Treatment area access is alsoprovided through the seal strip. The system can also be employed as ahemostat.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constitute a part of this specification and includeexemplary embodiments of the present invention and illustrate variousobjects and features thereof.

FIG. 1 is a schematic, block diagram of a tissue closure treatment andsystem embodying the present invention.

FIG. 2 is a perspective view of an incision tissue separation with adeep drain tube installed.

FIG. 3 is a perspective view thereof, showing the separated tissuesutured together at the skin.

FIG. 4 is a perspective view thereof, showing the separated tissuesutured together at the deep dermal layer below the skin surface.

FIG. 5 is a perspective view thereof, showing a rayon strip primaryfluid transfer component (FTC.1) and an underdrape being placed on thestitch line.

FIG. 6 is a perspective view thereof, showing FTC.1 and the underdrapein place on the stitch line.

FIG. 7 is a perspective view thereof, showing a secondary fluid transfercomponent (FTC.2) in place.

FIG. 8 is a perspective view thereof, showing an overdrape in place.

FIG. 9 is a perspective view thereof, showing a connecting fluidtransfer component (FTC.3) in place for connecting the system to anegative pressure source.

FIG. 10 is a cross-sectional view thereof, taken generally along line10-10 in FIG. 9 and particularly showing FTC.3.

FIG. 11 a is a perspective view thereof, showing FTC.3 removed and theoverdrape scored for ventilation.

FIG. 11 b is a perspective view thereof, showing the patient interfaceremoved along a perforated tear line in the underdrape and a slit linein the overdrape.

FIG. 11 c is a perspective view of a patient interface adapted forprepackaging, application to a patient and connection to a negativepressure source.

FIGS. 12 a-d show alternative embodiment elbow connecting devices FTC.3a-d respectively.

FIGS. 12 e,f show a modified FTC.2 a with removable wedges to facilitatearticulation, such as flexure of a patient joint.

FIGS. 12 g,h show alternative embodiment external patient interfaceassemblies.

FIGS. 13 a-c comprise a flowchart showing a tissue closure treatmentmethod embodying the present invention.

FIG. 14 is a schematic, block diagram of an automated tissue closuretreatment system comprising an alternative embodiment of the presentinvention.

FIG. 15 is a cross-sectional view of the alternative embodimentautomated tissue closure treatment system.

FIG. 16 is a partial flowchart of an alternative embodiment automatedtissue closure treatment method embodying the present invention.

FIG. 17 is a fragmentary, perspective view of a tissue closure treatmentsystem comprising an alternative embodiment of the present invention,with a reclosable access panel.

FIG. 18 is a perspective view of the reclosable access panel.

FIG. 19 is a cross-sectional view of the tissue closure treatmentsystem, taken generally along line 19-19 in FIG. 18.

FIG. 20 is an enlarged, cross-sectional view of the tissue closuresystem, particularly showing a reclosable seal strip thereof.

FIG. 21 is a perspective view of the tissue closure system, showing theseal strip open.

FIG. 22 is a perspective view of the tissue closure system, showing theseal strip open and a foam piece removed.

FIG. 23 is a cross-sectional view of an external dressing assembly,which comprises an alternative embodiment of the present invention.

FIG. 24 is a cross-sectional view of an alternative embodiment tissueclosure system with internal and external foam pieces.

FIG. 25 is a cross-sectional view of the system shown in FIG. 24,showing the progressive healing of tissue in the wound.

FIG. 26 is a cross-sectional view of the system shown in FIG. 24,showing the reepithelialization of the wound.

FIG. 27 is a cross-sectional view of a foam piece partially enclosed inrayon.

FIG. 28 is a cross-sectional view of an alternative embodiment tissueclosure system, with an external foam piece and an internal foam pieceassembly.

FIG. 29 is a cross-sectional view thereof, shown partially collapsedunder ambient atmospheric pressure.

FIG. 30 is a perspective view of an alternative construction dressingwith a reclosable seal strip and fluid access ports.

FIG. 31 is a perspective view of the underside of the dressing, showinga middle backing strip being removed.

FIG. 32 is a perspective view of the dressing, showing side backingstrips being removed.

FIG. 33 is a perspective view of the dressing, shown with a squeeze bulbevacuator attached to a fluid port thereof.

FIG. 34 is a perspective view of the dressing, shown partially-collapsedunder atmospheric pressure.

FIG. 35 is a perspective view of the dressing, shown with the seal stripopen.

FIG. 36 is a perspective view of the dressing, shown with the foam pieceremoved.

FIG. 37 is a cross-sectional view of a foam piece fully-enclosed inrayon.

FIG. 38 is a perspective view of an alternative embodiment dressing witha separate liner and foam piece.

FIG. 39 is a perspective view of the dressing, shown with the foam piecefor moved.

FIG. 40 is a perspective view of the dressing, shown with the linerremoved.

FIG. 41 is a cross-sectional view of an alternative embodiment dressingwith a sheath bottom panel comprising a wicking material.

FIG. 42 is a cross-sectional view of an alternative embodiment dressingsystem with a covered foam-core transfer element.

FIG. 43 is a cross-sectional view thereof, showing the dressingcompressed under pressure.

FIG. 44 is a top plan view thereof.

FIG. 45 is a cross-sectional view thereof, showing the dressingconfiguration prior to application to a patient and taken generallyalong line 45-45 in FIG. 44.

FIG. 46 is a top plan view of an application involving multipledressings covering an elongated tissue separation, such as a surgicalincision.

FIG. 47 is a perspective view of a wound with drain strips installed inpreparation for closure.

FIG. 48 is a cross-sectional view of a dressing comprising analternative embodiment of the present invention with upper and lowerrayon layers.

FIG. 49 is a cross-sectional view thereof, with the dressing compressed.

FIG. 50 is a cross-sectional view of a dressing comprising analternative embodiment of the present invention with a rayon coverenclosing a reticulated foam core.

FIG. 51 is a cross-sectional view thereof, with the dressing compressed.

FIG. 52 is a cross-sectional view of a dressing comprising analternative embodiment of the present invention with a sensor connectedto a controller.

FIG. 53 is a perspective view of an experimental model of the dressingfor observing fluid flow therethrough.

FIG. 54 is a graph showing wetted surface area of the reticulated foamcore with respect to liquid volume for different conditions.

FIG. 55 is a cross-sectional view of a hemostat comprising analternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

I. Introduction and Environment

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention, which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure.

II. Tissue Closure System 2

Referring to the drawings in more detail, the reference numeral 2generally designates a tissue closure treatment system embodying thepresent invention. As shown in FIG. 1, the system 2 is adapted for useon a patient 4 with an incision or wound 6, which can be closed by astitch line 8 consisting of sutures 10, staples or other suitablemedical fasteners.

A patient interface 12 consists of an optional deep drain 14 connectedto a deep drain negative pressure source 15 associated with a deepdrainage reservoir 17 and an external patient interface 16 including aprimary fluid transfer component FTC.1 comprising a strip of rayon orother suitable porous material, an underdrape 20 generally coveringFTC.1 and including a slot 20 a, a secondary fluid transfer componentFTC.2 comprising a hydrophobic sponge and an overdrape 24.

A fluid handling subsystem 26 includes the deep drain negative pressuresource 15 and a surface drain negative pressure source 28, which can becombined for applications where a common negative pressure source and acollection receptacle are preferred. The negative pressure sources 15,28 can operate either manually or under power. Examples of both typesare well-known in the medical art. For example, a manually operableportable vacuum source (MOPVS) is shown in U.S. Pat. No. 3,115,138,which is incorporated herein by reference. The MOPVS is available fromZimmer, Inc. of Dover, Ohio under the trademark HEMOVAC®. Bulb-typeactuators, such as that shown in U.S. Pat. No. 4,828,546 (incorporatedherein by reference) and available from Surgidyne, Inc. of Eden Prairie,Minn., can be used on smaller wounds, for shorter durations or inmultiples. Moreover, power-actuated vacuum can be provided by vacuumassisted closure equipment available under the trademark THE VAC® fromKinetic Concepts, Inc. of San Antonio, Tex. Still further, manyhealth-care facilities, particularly hospitals and clinics, are equippedwith suction systems with sources of suction available at wall-mountedoutlets.

A finite capacity reservoir 30 is fluidically connected to the negativepressure source 28 and is adapted to discharge to a waste receptacle 32.A shut-off valve 34 is associated with the reservoir 30 and is adaptedto automatically discontinue drainage when the reservoir 30 is filled toa predetermined volume.

An optional autotransfusion subsystem 36 can be connected to the deepdrain 14 and is adapted for reinfusing the patient 4 with his or her ownblood. U.S. Pat. No. 5,785,700 discloses such an autotransfusion systemwith a portable detachable vacuum source, which is available fromZimmer, Inc. and is incorporated herein by reference.

FIG. 2 shows an incision 6 forming first and second separated tissueportions 38 a,b with incision edges 40 a,b. The incision 6 extends fromand is open at the skin 42, through the deep dermal layer 44 and thesubcutaneous layer 46, to approximately the fascia 48. A deep drain tube50 is placed in a lower part of the incision 6 and penetrates the skin42 at an opening 52.

FIG. 3 shows the incision edges 40 a,b secured together by sutures 54forming a stitch line 56 at the skin surface 42. As an alternative tosutures 54, various other medical fasteners, such as staples, can beused. FIG. 4 shows sutures 55 placed in the deep dermal layer 44 belowthe skin surface 42.

FIG. 5 shows application of FTC.1 on top of the stitch line 8. FTC.1preferably comprises a suitable porous wicking material, such as rayon,which is well-suited for wicking the fluid that exudes along the stitchline 8. Rayon also tends to dry relatively quickly, and thus efficientlytransfers fluid therethrough. The underdrape 20 is placed over FTC.1 andthe adjacent skin surface 42. Its slot 20 a is generally centered alongthe centerline of FTC.1 and directly above the stitch line 8. FTC.1 andthe underdrape 20 can be preassembled in a roll or some other suitableconfiguration adapted to facilitate placement on the stitch line 8 inany desired length. FIG. 6 shows FTC.1 and the underdrape 20 in place.

The secondary fluid transfer component FTC.2 is shown installed in FIG.7. It preferably comprises a suitable hydrophobic foam material, such aspolyurethane ether (PUE), which comprises a reticulated, lattice-like(foam) material capable of being collapsed by vacuum force (negativepressure) in order to exert positive “shrink-wrap” type compression onskin surface and still maintain channels that allow passage of fluid. Asshown, its footprint is slightly smaller than that of the underdrape 20,thus providing an underdrape margin 20 b. The wicking layer of FTC.1can, as an alternative, be sized equal to or almost equal to thefootprint of FTC.2. This configuration lends itself to prefabrication asan individual, pre-assembled pad that can be employed by simply removinga releasing layer backing from an adhesive lined underdrape. Thisconfiguration also lends itself to easy total removal and replacement ofthe central part of the assembly without removing drape already adheredto skin if removal and replacement is the desired clinical option ratherthen staged removal or prolonged single application.

FIG. 8 shows the overdrape 24 applied over FTC.2 and the underdrape 20,with a margin 24 a extending beyond the underdrape margin 22 b andcontacting the patient's skin surface (dermis) 42. FIGS. 9 and 10 show apatch connector 58 mounted on FTC.2 and comprising a hydrophobic foam(PUE) material core 58 a sandwiched between drape layers 58 b. A vacuumdrain tube 60 includes an inlet end 60 a embedded in the foam core 58 aand extends between the drape layers 58 b to an outlet end 60 bconnected to the surface drainage negative pressure source 28.

FIG. 11 a shows FTC.3 removed, e.g. by cutting away portions of theoverdrape 24 to provide an overdrape opening 54. In addition, theoverdrape 24 can be slit at 55 to further ventilate FTC.2. DrainingFTC.2 under negative pressure, and further drying it with aircirculation (FIG. 11 a) can provide significant healing advantages byreducing the growth of various microbes requiring moist environments inFTC.2. Such microbes and various toxins produced thereby can thus beevaporated, neutralized and otherwise prevented from reentering thepatient. Microbe control can also be accomplished by introducingantiseptics in and irrigating various components of the patientinterface 12, including the drapes 20, 24; FTC.1; FTC.2; and FTC.3.

FIG. 11 b shows the patient interface 12 removed along underdrapeperforated tear lines 56 and slit lines 59 in overdrape 24. It will beappreciated that substantially the entire patient interface 12, exceptfor underdrape and overdrape margins 20 b, 24 a can thus be removed toprovide access to the stitch line 8 and the dermis 42 for visualinspection, evaluation, cleaning, stitch removal, dressing change (e.g.,with prepackaged patient interface 12 a as shown in FIG. 11 c),consideration of further treatment options, etc. For example, theoverdrape 24 can be slit to around the perimeter or footprint of FTC.2to permit removing the same. Preferably FTC.2 is easily releasable fromthe underdrape 20 and FTC.1 whereby FTC.2 can be grasped and liftedupwardly to facilitate running a scalpel through the overdrape 24 andinto a separation between the underside of FTC.2 and the underdrape 20.The FTC.1 can then optionally be removed by tearing the underdrape 20along its tear lines 56 and removing same as shown in FIG. 11 b.

FIG. 11 c shows a prepackaged patient interface 12 a adapted for initialor “dressing change” application. Optionally, the rayon strip FTC.1 canhave the same configuration or “footprint” as the foam sponge FTC.2,thus eliminating the underdrape 20. The prepackaged patient interface 12a can be sterilely packaged to facilitate placement directly on a stitchline 8. Alternatively, the patient interface components can beprepackaged individually or in suitable groups comprising subassembliesof the complete patient interface 12. For example, the underdrape/FTC.1and the overdrape/FTC.2 subassemblies respectively can be prepackagedindividually. Various sizes and component configurations of the patientinterface can be prepackaged for application as indicated by particularpatient conditions. Preferably, certain sizes and configurations wouldtend to be relatively “universal” and thus applicable to particularmedical procedures, such as TJRs, whereby patient interface inventorycan be simplified. Alternatively, the individual components can beassembled in various sizes and configurations for “custom” applications.

FIGS. 12 a-d show alternative connecting fluid transfer components FTC.3a-d for connecting FTC.2 to the surface drainage negative pressuresource 28. FTC.3 a (FIG. 12 a) shows a patch connector with a similarconstruction to FTC.3 and adapted for placement at any location on theoverdrape 24. FTC.3 a is provided with a Leur lock connector 62. FTC.3 b(FIG. 12 b) comprises a strip of hydrophobic (PUE) foam materialpartially covered by an overdrape 64, which can be configured as a wraparound a patient's limb or extremity 66. FTC.3 c (FIG. 12 c) is anelbow-type connector. FTC.3 d (FIG. 12 d) is a bellows-type elbowconnector, which is adapted to accommodate deflection of the vacuumdrain tube 60.

FIGS. 12 e,f show an alternative construction of FTC.2 a with multiple,removable wedges 57 formed therein and adapted for accommodatingarticulation, such as joint flexure. The flexibility of FTC.2 a can thusbe considerably enhanced for purposes of patient comfort, mobility andflexibility. Such wedges can extend transversely and/or longitudinallywith respect to FTC.2 a. FTC.2 a functions in a similar manner with andwithout the wedges 57 in place or removed.

FIG. 12 g shows a modified patient interface 312 with the underdrape 20placed below FTC.1. This configuration permits removing FTC.1 withoutdisturbing the underdrape 20. FIG. 12 h shows a further modified patientinterface 412 with FTC.1 having the same configuration or footprint asFTC.2, whereby they can be fabricated and bonded together. In thisconfiguration the underdrape 20 can be omitted.

III. Treatment Method

FIGS. 13 a-c comprise a flowchart for a method embodying the presentinvention. From start 70 the method proceeds to patient diagnosis andevaluation at 72 and treatment plan at 74. Deep drains 14 are installedat 76 as necessary, and the incision is sutured at 78. Surface interfacecomponents 12 are applied at 80 and connected to the external components(i.e., negative pressure sources 15, 28) at 82. The collection reservoircapacity is preset at 84 based on such factors as nature ofwound/incision, blood flow, etc.

Phase 1

Deep drainage occurs at 86 and active surface drainage occurs at 88,both being influenced by the negative pressure sources 15, 28. Thenegative pressure source 28 causes the PUE foam FTC.2 to partiallycollapse, which correspondingly draws down the overdrape 24 and exerts apositive, compressive force on the closed wound or incision 6. In theclosed environment of the patient interface 12, such force iseffectively limited to ambient atmosphere. This limiting control featureprotects the patient from excessive force exerted by the patientinterface 12. The steady force of up to one atmosphere applied acrossthe closed wound or incision 6 functions similarly to a splint orplaster cast in controlling edema and promoting healing.

A “Reservoir Full” condition is detected at 90 and branches to aninterrupt of the surface drainage negative pressure at 92, after whichthe reservoir contents are inspected and disposed of at 94. If surfacebleeding is detected by visual inspection at decision box 96, the methodbranches to a “Discontinue Active Surface Drainage” step at 98. If thesuture line is actively draining at decision box 100, the method loopsto the active surface drainage step 88 and continues, otherwise activesurface drainage discontinues at 98, i.e. when the wound/incision isneither bleeding nor exuding fluids.

Phase 1 is generally characterized by deep drainage (interactive orpassive) and active surface drainage under the influence of manual orpowered suction. The normal duration is approximately two to three days,during which time post-operative or post-trauma swelling normallyreaches its maximum and begins to recede.

Phase 2

FIG. 13 b shows Phase 2 commencing with a “Staged Component Removal?”decision box 102. An affirmative decision leads to independentlydeactivating and removing components at 103, including discontinuingactive suction at 104, which transforms the hydrophobic PUE foam (FTC.2)internal pressure from negative to positive and allows the collapsedFTC.2 to reexpand at 106, potentially increasing surface compositepressure from ambient to positive. Preferably this transition occurswithout applying undue pressure to the surface from the decompressed,expanding FTC.2. During Phase 1, negative pressure (i.e.,suction/vacuum) tends to compress FTC.2 and correspondingly contractsthe overdrape 24, adding to the compression exerted by FTC.2. When theapplication of negative pressure discontinues, either manually orautomatically, FTC.2 re-expands against the constraints of the overdrape24, and in an equal and opposite reaction presses against the skin 42,particularly along the stitch line 8. FTC.2 can thus automaticallytransform from ambient to positive pressure simply by discontinuing theapplication of the vacuum source.

The positive pressure exerted on the skin 42 continues to compress andstabilize tissue along the suture line 8 (step 108) in order to reduceswelling and cooperates with the operation of FTC.1 and FTC.2 tocontinue drainage by evaporation at the suture line 8 at step 110. Anegative determination at decision box 102 leads to interface removal at112 and, unless treatment is to be terminated, stitch line inspectionand treatment at 113 and interface replacement at 114, which can involveall or part of the patient interface 12. The method then proceeds toPhase 3.

Phase 3

FIG. 13 c shows Phase 3 of the treatment method wherein deep drainage isdiscontinued and the tube(s) is removed at 118. The overdrape 24 andFTC.2 are removed at 120, 122 respectively. The underdrape 20 and FTC.1are preferably configured to permit visual inspection of the suture line8 therethrough at 124. When the suture line 8 has closed sufficiently,the underdrape 20 and FTC.1 are removed at 126 and the treatment ends at128. Alternatively and if indicated by the patient's condition, all orpart of the interface 12 can be replaced in Phase 3 and treatmentcontinued.

IV. Alternative Embodiment Tissue Closure System 202

FIG. 14 schematically shows a tissue closure system 202 comprising analternative embodiment of the present intention, which includes amicroprocessor or controller 204, which can be connected to one or moresensors 206 coupled to the patient interface 12 for sensing variousconditions associated with the patient 4. The microprocessor 204 can beprogrammed to operate a solenoid 208 coupled to a valve 210 associatedwith the reservoir 30 and controlling fluid flow induced by a negativepressure source 228 through its connection to the patient interface 12.

FIG. 15 shows the tissue closure system 202 with the microprocessor 204connected to multiple sensors 206 a,b,c each of which is associated witha flow control component, such as a valve, 210 a,b,c respectively. Eachflow control component 210 a,b,c is associated with a respectivenegative pressure source 228 a,b,c, which in turn controls fluiddischarge into canisters or reservoirs 212 a,b,c respectively. Forexample, the patient interface 12 can comprise an external patientinterface 16 as described above and a pair of deep drainage tubes 50a,b. The patient interface 12 includes an optional supply component 214,which can comprise one or more fluid reservoirs, pumps (manual orpowered) and associated controls, which can connect to themicroprocessor 204 for system control. The supply component 214optionally takes to one or more of the tubes 50, 60 for delivering fluidto the patient through the deep drainage tubes 50 or through theexternal patient interface 16. Such fluids can comprise, for example,antibiotics, and aesthetics, irrigating agents, growth factor, and anyother fluid beneficial in promoting healing, countering infection andimproving patient comfort.

The methodology of the treatment with the alternative embodiment tissueclosure system 202 is shown in FIG. 16 and generally involves modifiedpretreatment 230 and Phase 1 procedures. From “Start” the methodproceeds to a diagnosis/evaluation step 234, a treatment plan step 236,deep drain installation 238, suturing at 240, external interfacecomponent application 242, microprocessor programming 244 and connectionof the application components at 246, such as connection of the tubing.Phase 1 commences with deep drainage at 248, active suction interface at250 and a “Suture Line Actively Draining?” decision box 252. If thesuture line is actively draining, the method loops back to the activesuction interface step 250, otherwise (negative determination at 252) itproceeds to Phase 2.

V. Applications

Without limitation on the generality of useful applications of thetissue closure systems 2 and 202 of the present invention, the followingpartial list represents potential patient conditions and procedures,which might indicate application of the present invention.

-   -   Over closed tissue separations, such as surgical incisions.    -   Over joints where the incision is subject to movement and        stretching, such as arthrotomy, reconstructive proceedures,        cosmetic procedures, flaps, scar revisions, Total Joint        Replacement (TJR) procedures, i.e., hip, knee, elbow, shoulder        and foot.    -   Any wound in an area of thick or unstable subcutaneous tissue,        where splinting of skin and subcutaneous tissue might reduce        dehiscence of deep sutures.    -   Wounds over reconstructive procedures in which irregular        cavities are created. These include resection of tumors,        implants, bone, and other tissues. Changes in length and        geometry of limbs, and changes in size, position, and contour of        bones and other deep structures.    -   Wounds in which elimination and prevention of dead space is        important.    -   Treatment of hematomas and seromas.    -   Amputation stumps.    -   Abdominal, thoracic, flank, and other wounds in which splinting        of the wound might assist closing and mobilizing the patient        during the postoperative interval.    -   Wounds in areas of fragile or sensitive skin, where repeated        removal and replacement of tape or other adhesives might produce        pain, irritation, or blistering of skin in the vicinity of the        wound. Also where dressing changes might produce shear or        displacement of tissue so as to compromise primary wound        healing.    -   Wounds in cases where the patient wishes to bathe before the        skin has healed sufficiently to allow protection from        contamination with bath or shower water.    -   Wounds subject to contamination with feces, urine, and other        body fluids.    -   Pediatric, geriatric, psychiatric, and neurologic patients, and        other patients likely to disturb dressings and wounds.    -   Patients with multiple consultants and care givers, where        repeated inspection of the wound might compromise healing.    -   Deep closure and surface sutures and staples.    -   Any clean surgical or traumatic incision, open, or fully or        partially closed by sutures, or where the skin edges can be        apposed to a gap no wider than the width of the negative        pressure zone of the dressing, i.e. where the maximum separation        is less than or equal to the width of FTC.1 (rayon strip).    -   In cosmetic and reconstructive surgery, the systems and methods        of the present invention can control and conceal the effects of        early bleeding, exudation, ecchymosis, and edema of the wound.    -   In surgery on the limbs, where compression and drainage by this        method might eliminate or reduce the need for circumferential        compressive wrapping.    -   Tissue separations that are prone to protracted drainage, such        as hip and knee incisions, and tissue separations in patients        with health conditions, such as diabetes, that tend to inhibit        healing. Shortened hospital stays might result from swelling        reduction and control of drainage.        VI. Case Studies    -   General concept: sequential surface application of foam material        (FTC.2) to surgical site and other wounds. Air-drying at the        suture line is facilitated by the rayon strip (FTC.1).    -   Phase 1: deep drainage (drain tube(s)), active or passive;        active suction applied to surface PUE foam (placed on top of        surgical incision, drains bleeding and exudate from suture        line); active suction compresses PUE foam, thus applying        positive compression to the entire dissection field;        adhesive-lined film underdrape with an MVTR of 3-800 on skin        underlying PUE foam; rayon (or other suitable porous wicking        material) strip on suture line; similar type of adhesive film        overdrape (MVTR of 3-800) overlying PUE foam material.    -   Duration: approximately 2-3 days, i.e. effective time for active        drainage from incision/stitch line to cease and for suture line        to dry and heal.    -   Phase 2: Remove active suction by cutting off (elbow) connector        and leave FTC.2 in place. Released from suction, FTC.2 expands        against the overdrape and exerts positive pressure differential        on the operation site. May maintain continued mild compression        throughout Phase 2; residual drainage function through rayon        strip and into FTC.2 provides continued drying of suture line.        Deep drain tubes remain in place during Phase 2 for active deep        drainage.    -   Duration: approximately three days, i.e. days 3-6 after        operation.    -   Phase 3: remove overdrape and FTC.2; leave underdrape and rayon        strip in place; visually observe wound healing progress;        transparency desirable.    -   Duration: several (e.g., up to three) weeks.    -   Clinical trial confirmation: Closure of surgical site in upper        chest area in patient with severe healing problems showed        excellent results and rapid wound healing.    -   Subcuticular (subepidermal) sutures avoid conflict with rayon        strip and need for early suture removal, or pressure on skin        sutures beneath compressive black sponge.    -   Option: use pressure transducer for interface pressure mapping        of wound site and automate control and monitor pressures, flow,        etc.        VII. Alternative Embodiment Tissue Closure System 302.

A tissue closure system 302 comprising an alternative embodiment of thepresent invention is shown in FIGS. 17-22. The system 302 is adapted forclosing a wound 304 with an undermined area 306 just above the fasciaand an upper tissue separation 308 located primarily in the dermis andin the subcutaneous layer. A wedge-shaped internal fluid transfercomponent (foam piece) 310 is located in the tissue separation area 308and is installed between side drapes 312 located on either side of thewound 304. An external fluid transfer component (foam piece) 314 isplaced on top of the internal component 310 and the side drapes 312, andis covered by an outer drape 316. An optional innermost foam piece 330can be located in and sized to fit the undermined area 306 and cantransfer fluid and gradient forces to and from the internal foam piece310.

A reclosable access panel 318 is placed over an opening formed in theouter drape 316 and includes an adhesive-coated perimeter 320surrounding an adhesive-free center area 322 with a reclosable sealstrip 324 extending longitudinally down the centerline thereof. The sealstrip 324 includes a rib or bead 326, which is releasably captured in achannel 328 (FIG. 20).

In operation, the reclosable access panel 318 is adhesively securedaround its perimeter 322 to the outer drape 316 and provides access tothe foam pieces 310, 314 of the dressing system 302. For example, thefoam pieces 310, 314 can be changed (FIGS. 21 and 22), treatments can beapplied and wound healing progress can be visually monitored.

VIII. Alternative External Dressing 402.

FIGS. 23-27 show an external dressing 402, which can be premanufacturedor preassembled and used for various wound treatment and closureapplications. The dressing 402 includes a foam piece 404 partiallyenclosed in a rayon covering 406, which includes an open top 408 securedto an upper perimeter 410 of the foam piece 404, for example, bysutures, staples, adhesive or some other suitable mechanical fastener asshown at 412. The dressing 402 is preferably preassembled with an outerdrape 414 including a foam-covering central portion 416 and a perimeter,patient-contact skirt portion 418. A tucked margin 420 is formed at theintersection of the drape portions 416, 418 and partially underlies thefoam piece 404 in order to protect the skin and prevent the formation oflow-pressure, vacuum voids around the edge of the foam piece 404 whereatblistering could otherwise occur. In operation, the dressing 402 can beeasily changed by cutting around the margin 420, removing the foam piece404 and the drape outer portion 416. The wound can thus be inspected,cleaned, debrided, treated, etc. and a new dressing 402 put in place.The patient-contact skirt portion 418 of the original dressing canremain in place.

FIG. 23 shows a fluid flow (discharge) directional arrow 421 from anelbow coupling 417 and a discharge tube 419. Alternatively, fluid couldbe injected into the dressing 402 through the tube 419 and the coupling417. Hydraulic/pneumatic compressive force arrows 423 are shown in FIG.23 and represent the downward (i.e. into patient) forces, which can beestablished by compressing the foam piece 404 under suction and thenreleasing the negative pressure differential, thus transitioning thedressing to a positive pressure differential. In a positive pressuredifferential mode of operation, the dressing 402 controls edema bypressing the foam piece 404 against the tissue adjacent to the wound.There are many potential medical benefits from controlling edema in thismanner. For example, healing is promoted, scar tissue is minimized andpatient discomfort can be reduced.

FIG. 24 shows the external dressing 402 used in conjunction with aninternal foam piece 422, which is located below the dermis at the top ofthe subcutaneous layer. The internal foam piece 422 is adapted forapplying a pressure differential within the subcutaneous layer wherebytissue growth and closure are promoted. The inside/outside configurationof the dressing system shown in FIG. 24 can rehabilitate and makepliable a wound edge 424 that has contracted and become hard, immobileand edematous by applying pressure differentials across the external andinternal foam pieces 404, 422, such as compression (positive pressuredifferential) for edema control.

FIG. 25 shows the wound confined to the dermis 426 with another internalfoam piece 428 in place. The subcutaneous layer is substantially healed.FIG. 26 shows the external foam piece 404 in place alone for drawing thewound edges 430 together at the epidermis. FIG. 27 shows the externalfoam piece 404 covered on the sides and bottom by the rayon covering406, leaving an open top 408.

IX. Alternative Embodiment Dressing System 502

FIG. 28 shows yet another alternative embodiment internal/externaldressing system configuration 502 with an external foam piece 504similar to the foam piece 404 described above and an internal foamassembly 506 located in the dermis and in the subcutaneous layer. Theassembly 506 consists of a proximate internal foam piece 508, which canbe located at the bottom of the subcutaneous layer on top of the fasciain an undermined cavity 510 formed by the wound, and a distal internalfoam piece 412 located primarily in the dermis and the subcutaneouslayer portions of the wound between the external foam piece 504 and theproximate internal foam piece 508.

The dressing system configuration 502 can be configured and reconfiguredas necessary to accommodate various wound configurations in variousstages of healing. For example, the proximate internal foam piece 508can be removed when the undermined cavity 510 closes. Likewise, thedistal internal foam piece 512 can be removed when the subcutaneouslayer and the dermis have healed. Moreover, the foam pieces 504, 508 and512 can be replaced with different sizes of foam pieces as necessary inconnection with dressing changes and as the wound configuration changes.Such sizes and configurations can be chosen to optimize the beneficialeffects of pressure gradients (both positive and negative), fluidcontrol, edema control, antibacterial measures, irrigation and othertreatment protocols. Still further, the access panel 318 described abovecan be used in conjunction with the dressing system 502 in order toprovide access to the foam pieces thereof and to the wound itself.

FIG. 29 shows the internal/external dressing system 502 compressed underthe vacuum effects of an external vacuum source with the drape 316 drawntightly down on the compressed outer foam piece 504. Thus compressed,the system 502 is adapted to transfer positive pressure differential,compressive forces to the area of the wound.

X. Alternative Embodiment Dressing Assembly 602

FIGS. 30-37 show a reclosable, preassembled external dressing assembly602 comprising an alternative embodiment of the present invention. Thedressing assembly 602 includes a foam piece 604, which can be completelycovered in rayon 606 or some other suitable material with the desiredabsorbent and/or wicking capabilities. The foam piece 604 also includesa core 605 comprising a suitable material, such as polyurethane,hydrophobic foam. Alternatively, other foam materials with hydrophobicor hydrophilic properties can be utilized. Various sizes and shapes ofthe foam piece 604 can also be employed, including cutting and trimmingit to size during the course of a medical procedure.

The foam piece 604 is removably placed in a reclosable sheath 608including a bottom panel 610 selectively covered by removable, adhesivebacking strips 612, 614 and 616 forming a central opening 618. As shownin FIG. 31, a central opening 618 in the bottom panel 610 is initiallycovered by the center backing strip 614. Removing the center backingstrip 614 exposes the foam piece 604 through the opening 618. Thereclosable sheath 608 also includes a top panel 620 with a reclosableseal strip 622 extending from end-to-end and generally longitudinallycentered. The seal strip 622 can be similar in construction to thereclosable seal strip 324 described above. The top panel 620 alsoincludes fluid ports 324, 326, which can comprise, for example, Leurlock connectors or some other suitable fluid connection device.

The sheath 608 can comprise polyethylene or some other suitable materialchosen on the basis of performance criteria such as permeability,flexibility, biocompatibility and antibacterial properties. Variouspermeable and semi-permeable materials are commonly used as skin drapesin medical applications where healing can be promoted by exposure to aircirculation. The sheath 608 can be formed from such materials forapplications where continuous vacuum suction is available and thedressing 602 is not required to be airtight.

According to an embodiment of the method of the present invention, adressing assembly 602 can be premanufactured, or custom-assembled fromsuitable components for particular applications. In a premanufacturedversion, the dressing 602 is preferably presterilized and packaged insterile packaging.

A common application of the dressing 602 is on a recently-closedsurgical incision for controlling bleeding and other fluid exudate. Forexample, the dressing 602 can be placed on the patient with its bottompanel opening 618 located over a stitch line 636 (FIG. 36). The centerbacking strip 614 is peeled from the bottom panel 610 to expose theopening 618 and the adhesive 628 on the bottom panel 610 (FIG. 33). Theopening 618 provides a fluid transfer, which can also be provided byconstructing the sheath bottom panel 610 from a permeable material, orby providing other passage configurations therethrough. The dressing 602can then be placed on the patient, with the bottom panel adhesiveproviding temporary fixation. The side backing strips 612, 616 can thenbe removed, as shown in FIG. 32, and the bottom panel 610 completelysecured to the patient.

The fluid ports 624, 626 are adapted for either extraction or infusionof fluids, or both, depending on the particular treatment methodology.For extraction purposes a vacuum source can be attached to one or bothof the ports 624, 626, and can comprise a mechanical, powered pressuredifferential source, such as wall suction. Alternatively, hand-operatedmechanical suction can be provided, such as a suction bulb 630 (FIG. 33)or a Hemovac device available from Zimmer Corp. of Warsaw, Ind. Suchhand-operated suction devices can accommodate patient mobility and tendto be relatively simple to operate. Powered suction and fluid pumpdevices can be preprogrammed to provide intermittent and alternatingsuction and infusion, and to automatically respond to patient conditionfeedback signals. As shown in FIG. 33, the application of a negativepressure differential (suction) collapses the sheath 608 onto the foampiece 604. The various dynamic fluid forces and fluid movement effectsdescribed above can thus be brought into operation and controlled.

FIG. 34 shows the sheath 608 further collapsing on the foam piece 604 asa result of evacuation from both of the fluid ports 24, as indicated bythe fluid flow arrows 632. The ambient air pressure force arrows 634show the application of this force, which tends to collapse the sheath608 onto the foam piece 604.

FIG. 35 shows opening the seal strip 622 for access to the interior ofthe dressing 602. The foam piece 604 can then be removed, as shown inFIG. 36, whereby the stitch line 636 can be visually inspected and/ortreated. The foam piece 604 can be flipped over or replaced, asnecessary. FIG. 37 shows a cross-section of the foam piece 604, whichcan be completely covered in rayon or some other suitable wickingmaterial 606 in order to accommodate placement of either side againstthe stitch line 636.

XI. Alternative Embodiment Dressing Assembly 702

FIGS. 38-40 show a dressing assembly 702 comprising an alternativeembodiment of the present invention and including a foam piece 704comprising any suitable hydrophobic or hydrophilic foam material. Thefoam piece 704 is selectively and removably located in a sheath 708,which can be similar to the sheath 608 described above. A liner 706 cancomprise a piece of rayon or some other suitable material adapted towick fluid from the stitch line 636 into the foam piece 704, and furtheradapted to isolate the patient from direct contact with the foam piece704. The liner 706 can be sized to lay flat against the bottom panel ofthe sheath 708.

In operation, the dressing assembly 702 is adapted to utilize readilyavailable components, such as the foam piece 704 and the liner 706, in adressing adapted for wound inspection, wound treatment and componentchange procedures, all without having to remove the sheath or disturbits adhesive attachment to the patient. FIG. 39 shows removing the foampiece 704, which can be flipped over for reuse or replaced. FIG. 40shows removing the liner 706, which can also be easily replaced. Withthe liner 706 removed, the stitch line 636 is exposed for stitchremoval, inspection, treatment, irrigation and other procedures. Thesheath 708 can then be reclosed and vacuum-assisted and/or othertreatment can resume.

XII. Alternative Embodiment Dressing Assembly 802

A dressing assembly 802 comprising an alternative embodiment of thepresent invention is shown in FIG. 41 and includes a foam piece 804 in asheath 806 adapted for opening and closing through a reclosable sealstrip 808. The sheath 806 includes an upper drape portion 810, which cancomprise a suitable semi-permeable or impervious drape material. Thesheath 806 includes a perimeter 812, which can be provided with anoptional adhesive perimeter seal 813 adapted for providing a relativelyfluid-tight seal around the sheath 806. The perimeter seal 813 can berelatively narrow in order to minimize patient discomfort, skinmaceration, etc. A bottom panel 814 comprises a suitable wickingmaterial, such as rayon, and extends to the sheath perimeter 812. Thematerials comprising the dressing 802 can be chosen for permeability orocclusiveness, biocompatibility, hydrophobic or hydrophilic reaction toliquids, bacteriastatic and antimicrobial properties, and otherperformance-related properties and criteria.

In operation, the dressing 802 is placed on the patient over a wound orstitch line. The perimeter adhesive 813 can provide temporary fixationand sealing. A strip of tape 816 can be placed over the sheath perimeter812 for securing the sheath 806 in place. Fluid is transferred throughthe wicking material layer 814 to the foam piece 804 for evacuationthrough suitable fluid connectors, as described above, which can beattached to a vacuum source. Moreover, the dressing 802 is adapted forproviding a positive pressure gradient, also as described above. Theseal strip 808 permits access to the foam piece 804 for flipping over orchanging, as indicated.

The foam piece 804, the drape upper portion 810 and the wicking materiallayer 814 can be assembled for independent movement whereby the onlyattachment among these components occurs around the perimeter 812 wherethe drape upper portion 810 is connected to the wicking material layer814. Such independent freedom of movement permits the dressing assembly802 to reconfigure itself and conform to the patient and various appliedforces, such as pressure gradients. The individual components can thusexpand and contract independently of each other without distorting theother components or interfering with the performance and comfort of thedressing assembly 802.

XIII. Alternative Embodiment Dressing System 902

A dressing system 902 comprising another alternative aspect orembodiment of the present invention is shown in FIGS. 42-46 and includesa dressing 904 adapted for controlling the application of positive,compressive forces and/or negative, suction forces to a patient with anincision-type tissue separation 906. Without limitation of thegenerality of useful applications of the system 902, the incision 906can comprise a surgical incision, which can optionally be closed withstitches 908 or other suitable wound-closure procedures, includingstaples, adhesives, tapes, etc. The incision 906 can include a closedsuction drainage tube 910 in the base of the incision, which can bebrought to the skin surface through a stab incision, using well-knownsurgical procedures.

The dressing 904 includes a dressing cover 909 with an optionalperimeter base ring 912, which comprises a semi-permeable material witha layer of skin-compatible adhesive 914 applied to a lower face thereof.Prior to application of the dressing 904, the base ring adhesive 914mounts a release paper backing 916 (FIG. 45) with a release tab 917(FIG. 44). The base ring 912 defines a central, proximal opening 918,through which the dressing 904 is downwardly open. A coversuperstructure 920 includes a distal panel 922, a perimeter 924generally defining a folding, collapsible edge, and a proximal returnring 926 secured to the base ring 912 around the central opening 918 atanother folding, collapsible edge. The base and return rings 912, 926thus form an invaginated, double-thickness base structure 928 adapted toexpand and collapse. A distal cover opening 930 is formed in the distalpanel 922 and communicates with a flexible, bellows-shaped collapsiblesheath, which in turn mounts a length of rigid tubing 934 terminatingdistally in a connector 936 comprising, for example, a needle-free, leurlock hub or other suitable tubing connection/closure device, such as anair valve. The tubing 934 includes a proximal end 935 communicating withthe interior of the dressing cover 909.

An optional transfer assembly or element 938 is positioned within thecover 909 and is exposed through the central opening 918 thereof. Thetransfer assembly 938 optionally includes a compressible, reticulatedcore 940, which can comprise, for example, polyurethane ether foammaterial chosen for its hydrophobic, resilient and memory performancecharacteristics. The transfer assembly 938 also includes a porous,flexible liner 942 comprising a material such as Owens® rayon surgicaldressing with liquid-wicking properties and biocompatibility for directcontact with patients'skin.

Without limitation on the generality of useful applications of thedressing system 902, post-operative incision dressing applications areparticularly well-suited for same. The dressing 904 can be preassembledand sterile-packaged for opening under sterile conditions, such as thosetypically maintained in operating rooms. The central opening 918 can besized to accommodate the tissue separation 906 with sufficient overlapwhereby the perimeter base ring adhesive 914 adheres to healthy skinaround the area of the tissue separation 906 and beyond the area ofunderlying internal operative dissection. Multiple dressings 904 can beplaced end-to-end (FIG. 46) or side-by-side in order to effectivelycover relatively long incisions 950. In such multiple dressingapplications, the stitch line 952 can be covered with an interveningbarrier layer strip 948 at locations where the adhesive-coated base ringcrosses same for purposes of patient comfort. The barrier layer strips948 can comprise, for example: Xeroform® gauze available from IntegrityMedical Devices, Inc. of Elwood, N.J.; Vaseline® gauze; or straps ofOwens® rayon.

The base ring adhesive 914 preferably forms a relatively fluid-tightengagement around the treatment area. Optionally, the base ring 912 cancomprise a suitable semi-permeable membrane material, with suitablebreathability characteristics for enhancing patient comfort and avoidingmaceration in the contact areas. A suitable differential pressure source944 is coupled to the tubing connector 936. Without limitation, thepressure source 944 can comprise automated and manual pressure sources.For example, automated wall suction is commonly available in operatingrooms and elsewhere in health-care facilities.

For post-operative incision dressings, operating room wall suction canbe attached to the connector 936, the dressing 904 evacuated, and thewall suction disconnected whereby the connector 936 seals the system. Itwill be appreciated that a “steady-state” condition of equilibrium canbe achieved with positive, ambient air pressure acting externally on thedressing cover 909 and the transfer assembly 938 compressed internally,and thus exerting compressive forces on the incision 906 and thesurrounding area via compressive force arrows 939 (FIG. 43).

For example, FIG. 43 shows the dressing 904 collapsed with the rayondressing liner 942 extending beyond the polyurethane ether foam core 940and forming a double-thickness liner perimeter 946 located within thedouble-folded cover perimeter 924. In this configuration any liquidexudate from the incision 906 is effectively transferred by wickingaction of the rayon liner 942 away from the incision 906 via fluidtransfer arrows 941. Serosanguineous fluid emissions can be expectedfrom an incision line for a short period, commonly a day or two, afteran operation. The wicking action of the rayon liner 942, coupled withthe slight ambient air circulation admitted through the semi-permeablebase ring 912, cooperate to maintain the incision 906 and the healthyskin around it relatively dry in order to avoid maceration. The pressuredifferential provided by components of the dressing 904 can alsocontribute to extraction and removal of wound exudates, in cooperationwith the wicking action described above. With the dressing 904 in itscompressed configuration (FIG. 43), the tubing proximal end 935 canengage and be pushed into the transfer element 938 for direct fluidtransfer therebetween.

The evacuated dressing 904 provides a number of medical incision-closureand healing benefits. The stabilizing and fixating effects on theincision and the surrounding tissue resulting from the forces applied bythe dressing 904 tend to promote contact healing, as opposed to gaphealing or healing wherein opposing edges are sliding and moving one onthe other. Moreover, edema and ecchymosis control are accomplished byexerting positive pressure, compressive force via the compressive forcearrows 939 in the compressed core 940, which tends to resume itspre-compression shape and volume as pressure is released within thedressing 904. Thus, the effects of restricted or controlled leakage, forexample around the base ring 912, tend to be offset by the controlledexpansion of the core 940. The limited air movement through the dressing904 can be beneficial for controlling internal moisture, reducingmaceration, etc.

The system 902 is adapted for adjustment and replacement as necessary inthe course of closing and healing an incision. Additional airdisplacement can be applied via the connector 936 from automated ormanual sources. Wall suction, mechanized pumps and other automatedsources can be applied. Manual vacuum sources include: squeeze-typebulbs (630 in FIG. 33); (Snyder) Hemovac® evacuators available fromZimmer, Inc. of Warsaw, Ind.; and vacuum tubes. Inspection of theincision 906 can be accomplished by making an L-shaped cut in thedressing cover superstructure 920 and extracting or lifting the transferassembly 938, thereby exposing the incision 906. The transfer assembly938 can be flipped over or replaced. The dressing 904 can then beresealed by applying a replacement portion of the cover 909, whereafterthe dressing 904 can be evacuated as described above. After treatment iscompleted, the cover superstructure 920 can be cut away and the transferassembly 938 can be discarded. The base ring 912 can be peeled away fromthe skin, or simply left in place until the adhesive 914 releases.

The stabilizing, fixating and closing forces associated with thedressing 904 tend to facilitate healing by maintaining separated tissueportions in contact with each other, and by controlling and/oreliminating lateral movement of the tissue, which can prevent healing.The positive pressure, compressive force components associated with theforces in the dressing 902 tend to close the tissue separation 906 andretain the opposing tissue edges in fixed contact with each otherwhereby healing is promoted. Various other dynamic forces tending todisplace the wound edges relative to each other can be effectivelyresisted.

XIV. Alternative Embodiment External Dressings 1002, 1012

FIGS. 47-49 show another alternative embodiment external dressing 1002.As shown in FIG. 47, a wound 6 can be prepared by placing optional drainstrips 1004 between the wound edges and folding the strip distal endsover on the adjacent skin surface. The use of such strips is well-known.A latex version, which is referred to as a Penrose drain, is availablefrom Davol Inc. of Cranston, R.I. A silastic version, which is referredto as a Swanson incision drain, is available from Wright MedicalTechnology, Inc. of Arlington, Tenn. Alternative deep-wound devices forextracting fluid include drain tubes, such as those described above, andother devices. Alternatively, such drain devices can be omitted fromincisions that do not require enhanced drainage. Moreover, the drainstrips 1004 can be placed over a strip of liquid transfer liner, such asrayon, “veil” dressing or liner, “N-terface” liner, etc. to increaseefficiency and prevent skin maceration.

FIG. 48 shows the dressing 1002, which includes a fluid transfercomponent 1006 with a reticulated foam core or block 1008 (e.g.polyurethane-ether as described above) with a surface 1009 anddistal/upper and proximal/lower wicking material (e.g., rayon or othersuitable wicking material) layers 1010, 1012, which can optionally bebonded to or placed loose on the core 1008. A membrane drape 1014 isplaced over the fluid transfer component 1006 and releasably adhered tohealthy skin adjacent to the incision 6. An elbow coupling 417 is placedover an opening 1016 forming a discharge port in the membrane drape1014. The coupling 417 is attached to a suction or negative pressuresource, also as described above. Upon activation of the negativepressure source, fluid movement tends to be concentrated laterally(horizontally) along the bottom wicking layer 1012 towards the perimeterof the fluid transfer component 1006. The pressure differential betweenthe fluid transfer component 1006 and the ambient atmosphere compressesthe core 1008 as shown in FIG. 49. For example, compression in the rangeof approximately 20% to 80% is feasible. The rayon layers 1010, 1012 arethus drawn into closer proximity, particularly around the perimeter ofthe fluid transfer component 1006, whereby fluid transfer therebetweenis facilitated. Still further, the upper rayon layer 1010 tends to drawlaterally inwardly under negative pressure, whereas the lower rayonlayer 1012, because of being placed on the skin, tends to retain itsoriginal shape and size. The upper rayon layer 110, which is lesscompressible than the foam core 1008, thus tends to deflect downwardlyaround its perimeter edges, further facilitating fluid flow to the upperrayon layer 1010 and to the discharge coupling 417. The exposedperimeter edges of the core 1008 facilitate air movement into the core1008, e.g. through the membrane 1014, which can comprise asemi-permeable material.

FIGS. 50 and 51 show another alternative embodiment dressing assembly1022 with a foam core 1024 fully enclosed in a wicking material (e.g.rayon or other suitable wicking material) layer 1026. FIG. 51 shows thedressing 1022 after negative suction pressure is applied, which cancause the rayon layer 1026 to buckle or bunch adjacent to the lowerportions of the core perimeter edges, thereby providing an extended,buckled wicking material double-layer rim 1028. The rim 1028 can providean additional interface with the patient's skin, thereby avoiding orreducing pressure-related problems such as shearing force blistering.The rim 1028 can provide another benefit in the form of enhanced airflowfor the drying mode of skin maturation, which is a requirement of along-term (three days to three weeks) postoperative dressing.

Yet another alternative embodiment dressing system comprises the use ofthe dressing assembly 1012 during an initial heavy exudative phase,which typically occurs approximately 48-72 hours after a surgery. Thedressing 1002 can thereafter be removed and the rayon-enclosed dressingassembly 1022 applied for the long-term (typically about three days tothree weeks) postoperative transudative phase. Alternatively, a rayonwicking material layer alone can be applied to continue wicking-assistedfluid drainage of transudate. The tissues are thus stabilized forcritical early collagen strength gain and for removing transudate,thereby allowing for “sealing” of the incision 6 and the drain sites,and promoting drying the skin surface.

FIG. 52 shows yet another embodiment of the wound dressing 1032 with asensor 1034 in communication with the dressing 1032 and providing aninput signal to a controller 1036, which can include a feedback loop1038 for controlling various operating parameters of a system includingthe wound dressing 1032. For example, hemoglobin levels can bemonitored, as well as pressures, fluid flows, temperatures, patientconditions and various exudate and transudate characteristics.

FIG. 53 shows an experimental model 1042 of the dressing, which isoriented vertically to model fluid flow in the system. The fluid tendsto be present in the areas which are shown at the bottom 44 and alongthe sides 46, 48 of the reticulated polyurethane foam core 1050 anddefine a fluid transfer zone 1051. An air entrapment zone 1052, i.e. topand center of the foam core 1050, tends to trap air whereby the fluidtends to be drawn towards the outside edges. The polyurethane etherreticulated foam material thus tends to trap air interiorly and moveliquid exteriorly. In this configuration, the break point for theability to move liquid to the discharge elbow 417 occurs at a liquidvolume equal to approximately 10% of the volume of the non-compressedfoam core 1050. Liquid absorption in the reticulated foam can beenhanced by coating its passages with protein.

Table I shows the compression effect of the reticulated polyurethaneether foam material under various negative pressure levels.

TABLE I COMPRESSION EFFECT VOLUME (CC) % COMPRESSION FOAM BLOCK (DRY)283.34 15 WITH FILM DRAPE 258.91 68 WITH 50 mm Hg VAC 58.94 73 100 mm49.96 73 150 42.41 77 BACK TO 100 47.71 74 AIR RE-EQUILIBRATION 133.9528

FIG. 54 shows the total wetted surface area of the reticulatedpolyurethane foam as a function of total liquid volume added atdifferent pressures, with both uncoated and protein-coated foamconditions.

FIG. 55 shows an active, positive pressure hemostat 1062 comprising analternative embodiment of the present invention and including a patientinterface 1064 with a transfer component 1066 for placement against apatient and an overdrape 1068 placed thereover and fastened to thesurrounding skin. The transfer component 1066 can include an optionalliner or cover 1070 for direct engagement with the patient's skin if thematerial comprising a core 1069 is incompatible with direct skincontact. The transfer component 1066 communicates with a pressure source1067 via an elbow coupling 417 over an opening or discharge port 1072 inthe overdrape 1068. Applying negative pressure to the transfer component1066 results in a positive pressure being applied to the patient's skinvia the transfer component 1066. The hemostat 1062 is adapted forproviding localized compression to speed resorption of free fluid edema.Applications can include subdermal hemorrhages (e.g. 1074) and freeedema resorption in body cavities, internal organs and joints. Otherapplications can also utilize the active pressure hemostasis device1062, including poultice-type applications for enhancing absorption ofsurface-applied pharmaceuticals. As shown, the sensor 1034 and thecontroller 1036 can monitor various operating parameters for providingautomated control, particularly in connection with varying positivepressures exerted by the transfer component 1066. For example, visible,thermal and infrared indications of subdermal conditions can be detectedby the sensor 1034, which outputs corresponding signals for input to thecontroller 1036. Pressure can be cycled as appropriate, and terminatedupon certain predetermined conditions being achieved, e.g. resorption ofthe free edema corresponding to achieving the treatment objectives.

It is to be understood that while certain embodiments and/or aspects ofthe invention have been shown and described, the invention is notlimited thereto and encompasses various other embodiments and aspects.For example, various other suitable materials can be used in place ofthose described above. Configurations can also be adapted as needed toaccommodate particular applications. Still further, various controlsystems can be provided and preprogrammed to automatically respondappropriately to different operating conditions. Still further, thesystems and methods described above can be combined with various othertreatment protocols, pharmaceuticals and devices.

1. A surface-wound healing dressing including: a foam core with aperimeter and upper and lower surfaces; a fabric wick covering saidlower surface of the foam core; an overdrape cover assembly draped overthe wick-covered foam core for placing over a patient's skin and aroundthe wound; the cover assembly trapping liquid in the foam core; thecover assembly transferring air to the foam core; the cover assemblyincluding a cover return ring extending inwardly from the foam coreperimeter below the fabric wick and underlying a portion of the foamcore lower surface adjacent to the foam core perimeter; adhesive on thecover return ring for releasably attaching the foam core to thepatient's skin surface around said surface-wound below the foam coreperimeter; a drain in the overdrape cover assembly over the foam coreupper surface; a vacuum capable of applying negative pressure to thewound site, the vacuum connected to the drain; the wick spreadingpatient fluid from the wound laterally outwardly from the wound over thecover return ring and around and through the foam core; and the vacuumremoving patient fluid from the wick and out of the dressing through thedrain.
 2. The wound-healing dressing of claim 1 with a base ring betweenthe overdrape cover assembly and the patient's skin.
 3. Thewound-healing dressing of claim 1 wherein the overdrape cover assemblyincludes skin-compatible adhesive for attachment to the patient's skin.4. The wound-healing dressing of claim 3 with a release paper backing.5. The wound-healing dressing of claim 1 for healing skin followingincisional, skin graft, liposuction or breast surgery procedures.
 6. Themethod of applying the dressing of claim 1.